Watchman Nee explores the concept of the soul as the essence of human self-consciousness and personality, emphasizing that our intellect, emotions, and will are all integral parts of the soul. He explains that the Bible often equates the soul with the heart, suggesting that understanding a person's soul is key to understanding their true self. Nee highlights that the soul is not only a reflection of personality but also encompasses the natural life of man, where the terms 'soul' and 'life' are often used interchangeably in Scripture. This interconnectedness of soul and life illustrates the depth of human existence as defined by both spiritual and natural elements. Ultimately, the sermon calls for a deeper understanding of the soul-life as foundational to our identity and relationship with God.